Short answer
Baking soda is sodium bicarbonate, which typically reacts with an acidic ingredient in batter to produce leavening gas. Baking powder combines bicarbonate with its own acid ingredients; many US products react when moistened and again when heated. Their formulations and effects differ, so a recipe-specific adjustment is needed before substituting one for the other. 1 2
Baking powder contains baking soda as its base, but adds acid and stabilizers, making it a ready-to-use leavening system, unlike baking soda, which is a single compound.
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At a glance
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| Question | baking soda | baking powder |
|---|---|---|
| Composition | Sodium bicarbonate | Bicarbonate plus acid ingredients |
| Typical reaction in baking | With a recipe acid and moisture | With moisture; often again with heat |
What each thing is
Baking soda. Baking soda is sodium bicarbonate, a chemical leavener that normally reacts with an acidic ingredient after moistening to release carbon dioxide in baked goods. 1 2
Baking powder. Baking powder combines sodium bicarbonate with one or more dry acids and usually a starch or other separating agent. Moisture initiates its leavening reaction; some formulations release additional gas when heated. 1 2
Key differences
The key difference is whether the leavener supplies its own acid. Baking soda is bicarbonate alone and is normally paired with an acidic ingredient in the recipe. Baking powder includes both acid and base; its timing depends on whether the formulation is single- or double-acting. 1 2
How to tell them apart
Read the package name and ingredients: baking soda is sodium bicarbonate, while baking powder also supplies dry acid ingredients. Do not identify an unlabeled white powder by appearance or a casual kitchen test. 1
Where they overlap
Both are white, powdery chemical leaveners used to create rise in baked goods by producing carbon dioxide gas. Some recipes use both together to balance flavor, browning, and leavening needs. 1 2
Edge cases
Some US recipes call for both baking soda and baking powder when the acidic content is insufficient for full leavening, or when a specific flavor or texture is desired. Labels and formulations may vary by brand. 1 2
Why the distinction exists
Baking powder was developed to simplify baking by providing both acid and base in one product, allowing consistent leavening even when recipes lack acidic ingredients. This convenience supports a wider range of baked goods. 1 2
Common misconceptions
A common misconception is that baking soda and baking powder can be swapped in equal amounts. In reality, their chemical makeup and strength differ, so direct substitution does not yield equivalent results. 1 2
Examples
A US home baker making chocolate chip cookies checks the recipe: if it calls for baking soda, they ensure an acidic ingredient like brown sugar is present. If it calls for baking powder, they use it as is, regardless of acidity. 1 2
Sources
Sources checked October 3, 2026.
- King Arthur Baking — Baking soda versus baking powder. Leavening agents, acid and activation.
- Sally’s Baking Recipes — Baking powder versus baking soda. Ingredient composition and recipe examples.